Conclusion - Model-Driven and Software Product Line Engineering - page 241

variants binding the variation points defined in the variability
model. There are still numerous issues in SPLE: Variability
management, product derivation, core assets exploitation,
testing, traceability and tool support are some of these.
Model-driven engineering is another new trend in software
engineering. It considers that models and transformations are
governing software development. Thus, the whole software
development cycle is viewed as a process of creation, iterative
refinement, and integration of models. Models are first-
class entities that denote a viewpoint of a system. Each
model conforms to a metamodel making the grammar and
the constraints of a particular concern explicit. Domain-
specific modeling is used to develop software systems, and
it involves the use of a domain-specific modeling language
to represent the different concerns of an application domain.
Model transformations appear to be one of the most important
operations on models. They are software artifacts that
implement algorithms to transform models that conform
to source metamodels into models that conform to target
metamodels. Transformations are often classified as model-
to-model, model-to-text, or text-to-model transformations.
Transformations can use a declarative or an imperative style;
inthelatter,weexpressthetransformationscheduling.Vertical
transformations are model transformations crosscutting
the level of abstractions. Horizontal transformations are
mechanisms to transform models at the same level of
abstraction but integrating several concerns or points of view
of an application domain. MDE technologies are now mature
technologies and tool supports such as the Eclipse modeling
framework, the Topcased toolkit, and the oAW framework.
Model transformation languages exist as QVT, ATL, or the
Xtend and Xpand from oAW.
MDE appears as an effective technique for product
lines since it provides uniformity and abstraction for
software artifacts and processes. The ability to build complex
transformations is crucial to automate domain and application